The remote village of Monomoni, Kenya, is too far from cities and too sparsely populated to be part of the national grid. Now, however, it’s possible for a family of cow herders or a small business to buy prepaid solar power through a mobile phone.

Powerhive, a startup that builds solar, mobile-connected microgrids—small utilities that are usually built to power around 200 homes—started testing their system in Monomoni in 2012, and began expanding to 100 more rural villages around the country last year, along with others in the rest of the underpowered world. The company raised $11 million in December, and just raised another $20 million to expand even more.

It’s one part of a quickly-growing industry that many believe may be the best way to bring electricity to the 1.3 billion people around the world who still don’t have it.

Having access to around-the-clock power can sometimes actually be cheaper than what the poorest people in the world spend on energy now—which is often more than people pay in the developed world. In rural Bangladesh, electricity costs an average of $2.30 a kilowatt hour; in Western Europe, it costs almost eight times less. In unelectrified parts of Kenya, keeping a handful of small electronics charged or a light burning is an ongoing, expensive job.